OpenAI: GPT-5.3-Codex vs xAI: Grok 4.5
xAI: Grok 4.5 wins on more metrics (7 of 9), but the right pick depends on what you optimize for — see the breakdown below.
| Metric | OpenAI: GPT-5.3-Codex | xAI: Grok 4.5 |
|---|---|---|
| Intelligence Index | 44.3 | 53.8✓ |
| Coding Index | — | 72.4✓ |
| GPQA Diamond | 92% | 93%✓ |
| Design Arena Elo | 1203✓ | — |
| Speed (tokens/sec) | 63 | 74✓ |
| Latency | 2.6s | 655ms✓ |
| Input price /M | $1.75✓ | $2.00 |
| Output price /M | $14.00 | $6.00✓ |
| Context window | 400K | 500K✓ |
| Capabilities | ReasoningToolsJSONVision | ReasoningToolsJSONVision |